Conventionally, a washing machine was composed as shown in FIG. 31 and FIG. 32. Its constitution is described below.
As shown in FIG. 31, in an outer casing 1, an outer tank 3 is supported by a suspension 2, and a dewatering tank 4 serving also as a washing tank (hereinafter called dewatering tank 4) is provided in the outer tank 3. The dewatering tank 4 is opened at the top, so that the laundry can be loaded from the top. Agitating blades 5 are provided in the bottom, and multiple holes are opened in the side wall.
The dewatering tank 4 is fixed on a dewatering shaft 7 supported by a bearing 6 provided in the bottom of the outer tank 3. The agitating blades 5 are fixed on a washing shaft 9 supported by a bearing 8 inside of the dewatering shaft 7. This washing shaft 9 is connected to a reduction mechanism 10, and a pulley 12 is fitted to a washing side input shaft 11. In the mounting part of the pulley 12 of the washing side input shaft 11, four sides are cut off, and the mounting hole of the pulley 12 has a fitting shape, and the torque of the pulley 12 is transmitted. The pulley 12 is connected to a drive motor 14 through a belt 13. The washing side input shaft 11 has a clutch mechanism 15 for transmitting the rotation of the drive motor 14 by changing over to the washing shaft 9 or dewatering shaft 7.
The clutch mechanism 15 comprises, as shown in FIG. 32, a clutch input boss 15d having a hole in a shape to be fitted into the cut portion of the four sides provided in the washing side input shaft 11, a clutch spring 15b, a control pawl 15e formed by bending the end of the clutch spring 15b, a release sleeve 15c having a notch for fitting the control pawl 15e formed by bending the end of the clutch spring 15b, clutch drive means 15a to be engaged with a stopper 15f of the release sleeve 15c, and a clutch output boss 15g of the dewatering shaft 7 on which the clutch spring 15b is wound.
In this constitution, in the washing and rinsing stroke, when the clutch drive means 15a of the clutch mechanism 15 is engaged with the stopper 15f of the release sleeve 15c, and the control pawl 15e formed by bending the end of the clutch spring 15b is fixed, the clutch spring 15b cannot be wound around the clutch input boss 15d, and if the clutch input boss 15d rotates, rotation cannot be transmitted to the clutch output boss 15g of the dewatering shaft 7. Rotation of the drive motor 14 is transmitted only to the agitating blades 5 through the washing shaft 9, and mechanical force is given to the laundry. Thus, washing and rising of the laundry contained in the dewatering tank 4 are progressed.
In the dewatering stroke, when the clutch drive means 15a of the clutch mechanism 15 is disengaged from the stopper 15f of the release sleeve 15c, and the control pawl 15e formed by bending the end of the clutch spring 15b is set free, the clutch spring 15b is wound around the clutch input boss 15d. Accordingly, when the clutch input boss 15d rotates, rotation is transmitted to the clutch output boss 15g of the dewatering shaft 7. Rotation of the drive motor 14 is transmitted only to the dewatering tank 4 through the dewatering shaft 7, and the entire dewatering tank 4 is put into rotation. As the dewatering tank 4 rotates, the water in the laundry after washing and rinsing is wrung out by centrifugal force into the outer tank 3 through multiple holes opened in the side wall of the dewatering tank 4. Thus, the laundry is dewatered automatically.
In such conventional washing machine, the drive motor 14 is transmitting power to the reduction mechanism 10 through the belt 13. Accordingly, if one attempts to apply a larger mechanical force to the laundry in order to increase the washing capacity or to enhance the cleaning power, transmission torque is defined by the upper limit by belt slip, belt elongation, belt breakage, or tension changes of the belt 13 due to time-course changes, and transmission torque corresponding to large capacity cannot be obtained.
Moreover, since heavy objects, that is, the drive motor 14 and the reduction mechanism 10, are disposed side by side beneath the outer tank 3, the position of the center of gravity of the dewatering tank 4 and outer tank 3 suspended in the outer casing 1 is deviated from the center of rotation (dewatering shaft 7) of the dewatering tank 4. Therefore, in dewatering rotation of the dewatering tank 4, the balance is likely to be broken, and vibration due to rotation becomes larger.
To solve such problems, a washing machine constituted as shown in FIG. 33 has been proposed.
As shown in FIG. 33, an outer tank 16 is suspended by a plurality of suspensions 18 in an outer casing 17, and inside of the outer tank 16. Moreover, there is a dewatering tank 20 serving also as washing tank (hereinafter called dewatering tank 20) which is fixed to the upper end side of a dewatering shaft 19 and is rotated by the dewatering shaft 19. At the side of the dewatering tank 20, a plurality of water passing holes 21 are formed, and a liquid balancer 22 is disposed at the upper opening, so that the laundry may be loaded through the upper opening.
A bearing 21 supports the dewatering shaft 19, and is provided in the bottom of the outer tank 16. A washing shaft 24 is disposed inside of the hollow dewatering shaft 19, and is disposed to be coaxial with the dewatering shaft 19. At the upper end of the washing shaft 24, agitating blades 25 are provided rotatably in the inner bottom of the dewatering tank 20, and a rotor 27 of a drive motor 26 is connected to the lower end. The drive motor 26 comprises the rotor 27 and a stator 28 disposed oppositely to a magnet provided on the outer circumference of this rotor 27, and the rotor 27 is rotated by the rotary magnetic field of the stator 28. Between the lower end of the dewatering shaft 19 and the rotor 27, a clutch mechanism 30 is provided through a coupling 29, and by changing over the clutch mechanism 30, rotation of the rotor 27 is transmitted or not transmitted to the dewatering shaft 19.
In this constitution, in the washing and rinsing stroke, the clutch mechanism 30 is changed over, and the dewatering shaft 19 and rotor 27 are cut off. Therefore, the rotation of the rotor 27 of the drive motor 26 is transmitted only to the agitating blades 25 through the washing shaft 24, and a mechanical force is given to the laundry. Thus, washing and rinsing of the laundry contained in the dewatering tank 20 are progressed.
In the dewatering stroke, the water in the dewatering tank 20 is discharged, the clutch mechanism 30 is changed over, and the dewatering shaft 19 and rotor 27 are coupled, thereby rotating the washing shaft 24, dewatering shaft 19 and dewatering tank 20 coupled to the rotor 27 of the drive motor 26. As the dewatering tank 20 rotates, the water in the laundry after washing and rinsing is wrung out into the water tank 16 from multiple water passing holes 21 provided in the side of the dewatering tank 20 by centrifugal force. Thus, the laundry is dewatered.
In the washing machine of such constitution, however, in order to effectively suppress any imbalance in the dewatering stroke, the center of rotation of the dewatering shaft 19 and the washing shaft 24 were disposed coaxially with the rotary shaft of the drive motor 26 by using a coupling 30. The position of center of gravity of the dewatering tank 20 and outer tank 16 was also matched nearly with the position of center of gravity of the drive motor 26. It therefore required alignment of the coupling 30, the assembling performance was poor, and the washing machine was higher by the portion of the height of the coupling 30, which added to the cost.